Add http server

cmd/serve.go

@@ -0,0 +1,165 @@
+/*
+Copyright © 2022 NAME HERE <EMAIL ADDRESS>
+
+*/
+package cmd
+
+import (
+	"bytes"
+	"fmt"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/saunaclub/inkpot-cli/epd"
+	"github.com/spf13/cobra"
+)
+
+var defaultWidth int = 540
+var defaultHeight int = 960
+var port int
+
+type Params struct {
+	Width  int    `form:"height"`
+	Height int    `form:"width"`
+	Url    string `form:"url"`
+}
+
+// serveCmd represents the serve command
+var serveCmd = &cobra.Command{
+	Use:   "serve",
+	Short: "Run a webserver to convert images via HTTP",
+	Run: func(cmd *cobra.Command, args []string) {
+		router := gin.Default()
+		// Set a lower memory limit for multipart forms (default is 32 MiB)
+		router.MaxMultipartMemory = 8 << 20 // 8 MiB
+		router.GET("/", getIndex)
+		router.GET("/convert", getConvert)
+		router.PUT("/convert", putConvert)
+		router.Run(fmt.Sprintf(":%d", port))
+	},
+}
+
+func getIndex(c *gin.Context) {
+	usage := `# inkpot-convert
+
+A webserver to convert GIFs, PNGs and JPEGs to 4-bit grayscale images.
+
+## Routes
+
+- PUT /convert can be used to convert a file on your filesystem
+- GET /convert/[url] can be used to convert a file publically accessible via URL
+
+Both routes accept a "width" and a "height" parameter to configure the output size.
+
+## Examples
+
+Via curl:
+
+curl -X PUT http://localhost:8080/convert \
+  -F "file=@my_cat.jpeg" \
+  -H "Content-Type: multipart/form-data"
+
+Via httpie:
+
+http --form PUT :8080/convert file@my_cat.jpg
+`
+
+	c.String(http.StatusOK, usage)
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func getConvert(c *gin.Context) {
+	var params Params
+	err := c.ShouldBindQuery(&params)
+	if err != nil {
+		c.Error(err)
+	}
+
+	if params.Url == "" {
+		c.String(http.StatusBadRequest, "Please supply an image URL.")
+		return
+	}
+
+	width := min(params.Width, 2000)
+	height := min(params.Height, 2000)
+	if width <= 0 {
+		width = defaultWidth
+	}
+	if height <= 0 {
+		height = defaultHeight
+	}
+
+	response, err := http.Get(params.Url)
+	if err != nil || response.StatusCode != http.StatusOK {
+		c.Status(http.StatusServiceUnavailable)
+		return
+	}
+
+	reader := response.Body
+	defer reader.Close()
+
+	converted, err := epd.ConvertImage(reader, width, height)
+	if err != nil {
+		c.Error(err)
+	}
+
+	extraHeaders := map[string]string{
+		"X-Image-Width":  fmt.Sprintf("%d", width),
+		"X-Image-height": fmt.Sprintf("%d", height),
+	}
+
+	c.DataFromReader(http.StatusOK, int64(len(converted)), "x-image/inkpot-epd", bytes.NewReader(converted), extraHeaders)
+}
+
+func putConvert(c *gin.Context) {
+	var params Params
+	err := c.ShouldBindQuery(&params)
+	if err != nil {
+		c.Error(err)
+	}
+
+	width := min(params.Width, 2000)
+	height := min(params.Height, 2000)
+	if width <= 0 {
+		width = defaultWidth
+	}
+	if height <= 0 {
+		height = defaultHeight
+	}
+
+	// Single file
+	file, err := c.FormFile("file")
+	if err != nil {
+		c.Error(err)
+	}
+
+	reader, err := file.Open()
+	if err != nil {
+		c.Error(err)
+	}
+	defer reader.Close()
+
+	converted, err := epd.ConvertImage(reader, width, height)
+	if err != nil {
+		c.Error(err)
+	}
+
+	extraHeaders := map[string]string{
+		"X-Image-Width":  fmt.Sprintf("%d", width),
+		"X-Image-height": fmt.Sprintf("%d", height),
+	}
+
+	c.DataFromReader(http.StatusOK, int64(len(converted)), "x-image/inkpot-epd", bytes.NewReader(converted), extraHeaders)
+}
+
+func init() {
+	rootCmd.AddCommand(serveCmd)
+	serveCmd.Flags().IntVarP(&port, "port", "p", 8080, "port to bind to")
+	// gin.SetMode(gin.ReleaseMode)
+}